This invention relates to a process for the production of diketo dinitriles, in particular, diketo dinitriles such as 3,11-dioxotridecanedinitrile (1,11-dicyanoundecane-2,10-dione) and to polymers derived therefrom.
U.S. Pat. No. 2,853,509 describes a process for the production of diketo dinitriles, or di-.beta.-ketonitriles as they may also be called, of the general formula EQU N.tbd.--C--CHR--C(O)--(CH.sub.2).sub.n --C(O)--CHR--C.tbd.N
wherein R is hydrogen, phenyl or alkyl and wherein n is an integer of from 1 to 8. The diketo dinitriles are produced by reacting in liquid ammonia the sodium derivative of a nitrile of the general formula EQU Na--CHR--C.tbd.N
wherein R possesses one of the aforestated meanings with a diester of the formula EQU R.sup.1 --O--C(O)--(C.sub.1 H.sub.2).sub.n --C(O)--O--R.sup.1
wherein R.sup.1 is alkyl of from 1 to 12 carbon atoms and n possesses the aforestated meaning. This process requires the use of liquid ammonia which must be kept at temperatures of -33.degree. C. or lower to remain in the liquid state. This requirement alone makes the process undesirable as an industrial synthesis. Another drawback to the process of U.S. Pat. No. 2,853,509 is that it employs sodium metal to make sodamide which in turn is used to make the aforementioned nitrile reactant. Sodium metal poses a severe fire risk and requires elaborate precautions for its safe storage and handling.
Accordingly, there has heretofore been a need for a method for the production of diketo dinitriles which does not require the use of liquid ammonia and/or sodium metal.